Wal-Mart Stores announced Tuesday that it will launch its own video downloads service this week beginning with an exclusive "Superman Returns" DVD bundle containing a video download option with purchase of the physical DVD.

Wal-Mart currently accounts for about 40 percent of all DVD sales in the United States. By launching its own service, industry watchers say Wal-Mart can protect that DVD market dominance.

In a press release, Wal-Mart said the service would be available to its customers on Wednesday in all Wal-Mart stores nationwide.

With the purchase of the "Superman Returns" physical DVD, Wal-Mart said customers can also choose from three video download format options -- $1.97 for portable devices, $2.97 for PCs/laptops, and $3.97 for both portable players and PC/laptops.

The retailer said the physical/digital DVD bundle would offer customers the flexibility to watch the Warner Bros. movie on their TV, portable devices as well as their computers.